Interpreting confidence intervals: A comment on Hoekstra,Morey, Rouder,and Wagenmakers (2014)

Hoekstra, Morey, Rouder, and Wagenmakers (Psychonomic Bulletin & Review 21(5), 1157–1164 2014) reported the results of a questionnaire designed to assess students’ and researchers’ understanding of confidence intervals (CIs). They interpreted their results as evidence that these groups “have no reliable knowledge about the correct interpretation of CIs” (Hoekstra et al. Psychonomic Bulletin & Review 21(5), 1157–1164 2014, p. 1161). We argue that their data do not substantiate this conclusion and that their report includes misleading suggestions about the correct interpretations of confidence intervals.